JPH04255671A - Alkaline dry battery - Google Patents

Abstract

PURPOSE:To prevent discharge abnormality due to corrosion of a collector rod in low amalgamation by using a Cu-Sn-Zn alloy containing specific wt.% of Sn as a raw material for contituting the collector rod. CONSTITUTION:In an alkaline dry battery provided with a positive electrode active material cocentrically filled in a positive electrode can, a sepqrator, a negative electrode active material and a negative electrode collector rod inserted through the center of this negative electrode active material, a collector rod is composed of a Cu-Sn-Zn alloy containing 1 to 4wt.% of Sn. The reason why a lower limit of the contents of Sn here is made 1wt.% is that, when the contents are less than this value, a corrosion protection effect is lost. Further, the reson why the upper limit is made 4wt.%, is that, when this value is exceeded, maleability is lowered and a surface is roughened in the manufacture of the connector rod so as to lower a sealing property. Accordingly, it is desirable to be set within a prescribed range, and especially in consideration of not only a corrosion protective property but also embrittlement, 1 to 3wt.% is a desirable range.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] This invention relates to an alkaline dry battery that prevents discharge abnormalities due to corrosion of current collector rods.

0002
].

[Prior Art] Alkaline dry batteries generally include a positive electrode active material, a separator, and a negative electrode active material that are concentrically filled inside a positive electrode can, a negative electrode current collector rod inserted through the center of the negative electrode active material, and the negative electrode collector. The negative electrode terminal plate is connected to the top of the electric rod and is caulked and fixed to the opening of the positive electrode can via a sealing gasket.

[0003] Brass is usually used as the material for the negative electrode current collector rod used in this battery. When we investigated the discharge abnormality that occurred in this battery, dezincification corrosion was found on the brass current collector rod. It is thought that this corrosion reduces the current collection effect. This dezincification corrosion is largely influenced by the presence of dissolved oxygen in the alkaline electrolyte in the negative electrode, but in the past, some of the mercury in the zinc chloride powder that makes up the negative electrode active material oxidizes the brass. Since the zinc chloride powder and the current collector rod were brought into electrical contact and at the same time the current collector rod itself was protected from corrosion, no particular problem occurred.

0004

[Problem to be Solved by the Invention] However, in recent years, due to environmental issues, there has been an increasing demand for low-fragility products (products that use less mercury), and compared to the conventional 0.6% by weight mercury content, Technological developments with even lower levels of mercury and mercury-free products are underway. As a result, the corrosion-preventing function of the current collector rod due to the above-mentioned corrosion is reduced, and cases where discharge abnormalities occur due to dezincification corrosion of the current collector rod are increasing.

[0005] As one measure to prevent this corrosion, for example, Japanese Patent Laid-Open No. 1-30160 proposes a current collector rod in which the brass is coated with a zinc alloy.
Since the brass wire is immersed in molten zinc alloy, the outer diameter must be machined by grinding or drawing to adjust the size and shape of the current collector rod, which is cumbersome and costly. It was also unproductive.

By the way, the present inventor discovered that the current collecting rod was made of tin (Sn).
), it was confirmed that a corrosion-preventing effect can be obtained when the corrosion resistance is reduced. The present invention provides an alkaline dry battery that prevents discharge abnormalities due to corrosion of the current collector rod during low-intensity reduction without requiring any processing by using an alloy containing tin (Sn) as the material of the current collector rod itself. It is intended to.

[0007]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a positive electrode active material, a separator, and a negative electrode active material that are filled concentrically inside a positive electrode can, and a separator that is inserted into the center of the negative electrode active material. In the alkaline dry battery equipped with a negative electrode current collector rod, the current collector rod is made of a Cu-Sn-Zn alloy containing 1 to 4% by weight of Sn.

In the above alloys, the lower limit of the Sn content is set at 1% by weight because if the content is less than this value, there is no anticorrosion effect. The upper limit was set at 4% by weight because if it exceeds this value, the malleability decreases, the surface becomes rough in the production of the current collector rod, and the sealing performance tends to decrease. Therefore, it is desirable that the content be in the above range, and in particular, 1 to 3% by weight is a preferable range, taking into account not only corrosion resistance but also brittleness.

[0009]

[Function] According to the alkaline dry battery using the current collector rod with the above configuration, compared to the conventional negative electrode with a degree of filtration of 0.6% by weight and a normal brass wire used as the current collector rod, It was confirmed that even though the concentration was reduced to 0% by weight, no deterioration in continuous discharge performance was observed, and the desired effect could be obtained.

0010

[Example] Ordinary Cu with a standard degree of graining of 0.6% by weight
-LR6 type alkaline dry battery (1) using brass wire made of Zn (63% Cu, balance Zn) alloy as a current collector rod
LR6 type alkaline dry batteries (2) to (6) whose degree of oxidation was changed to 0.15.0% by weight and a current collector rod having an alloy composition with a Sn content within the range of the present invention were used.
R6 type alkaline dry batteries (7) to (11) and LR6 consisting of an alloy composition with a Sn content exceeding the range of the present invention
The alkaline dry cell (12) was continuously discharged under a 75 ohm load, and the discharge index was compared using the alkaline dry cell (1) as a reference value of 100.
The results shown are obtained.

[0011] The general structure of the LR6 type alkaline dry battery is that the positive electrode active material is concentrically filled inside the positive electrode can.
A separator, a negative electrode active material, a negative electrode current collector rod inserted through the center of the negative electrode active material, and are connected to the top of the negative electrode current collector rod and fixed by caulking to the opening of the positive electrode can via a sealing gasket. It consists of a negative electrode terminal plate and a negative terminal plate.

In addition, as shown in Figure 2, the initial voltage was 1.5V for each dry battery, and the duration until the final voltage reached 0.9V was measured. It takes a short time for normal cases to occur, and for normal cases it takes a long time.

From this result, the weight ratio of Cu:Sn:Zn is 63:1:36, 71:1:28, 63:3:34.
, 63:4:33, which is almost the standard alkaline battery (1
) was confirmed to have comparable performance.

[0014] In the conventional alkaline dry batteries using only brass wires with low or no braking compositions, the discharge performance deteriorates, suggesting that dezincification corrosion progresses.

[0015]

[Effects of the Invention] As described above, the alkaline dry cell of the present invention has discharge performance similar to that of conventional alkaline batteries, and can prevent discharge abnormalities associated with a low degree of filtration, as well as improve the current collector rod. Since the material itself has a corrosion-resistant effect, there is no increase in processing man-hours and therefore no increase in cost.

[Brief explanation of the drawing]

[Figure 1] Comparison of the continuous discharge index of alkaline dry batteries using current collector rods of various alloy ratios according to the present invention and alkaline dry batteries using current collector rods made of brass wires with normal and low degrees of filtration. This is a diagram.

FIG. 2 is a graph showing the characteristics from the start of discharge to the final voltage.

Claims (1)

[Claims] 1. An alkaline dry battery comprising a positive electrode active material, a separator, and a negative electrode active material concentrically filled inside a positive electrode can, and a negative electrode current collector rod inserted through the center of the negative electrode active material, wherein the An alkaline dry battery characterized in that the electric rod is made of a Cu-Sn-Zn alloy containing 1 to 4% by weight of Sn.